1. Field of the Invention
The invention relates generally to computer software and, more specifically, to the hierarchical display and navigation of document revision histories.
2. Description of the Related Art
Users create documents in a variety of different applications, such as word processors, spreadsheets, image editors, and computer-aided design (CAD) applications. A revision history of a document is typically thought of as the set of ordered operations a user has performed in the application to create or modify contents of the document. One useful aspect of a revision history is the ability to undo, redo, or modify an operation that is stored in the revision history. Some applications discard a revision history when the document is either saved or closed, while other applications store the revision history along with the document. A revision history is typically visualized or navigated using one of many available techniques, such as textual lists, instructions presented in natural language, enhanced screen shots, before-and-after thumbnails, animations or videos.
One drawback to an approach for displaying a document revision history implemented by many applications is that user operations are not grouped based on a hierarchical system. For complex applications, the number of user operations stored in a revision history can become quite large. Typically, each of the user operations is displayed in a similar manner to all other user operations and navigating through all the user operations may become difficult. Another drawback of many applications that store a revision history of a document is that the ability to utilize the information stored for a user operation may be limited. For example, in some applications, operations based on the document revision history may be limited to undoing the last user operation. Yet another drawback to current approaches for displaying a document revision history is that, for example, simply listing the document revision history may not provide a user with enough information to understand why a series of revisions were made, but merely informs the user which revisions resulted in the final document.
As the foregoing illustrates, what is needed in the art is an effective mechanism for displaying, navigating and interacting with information stored in a complete revision history of a document.